avoodworth: geological expedition to brazil and chile. 83 



rather than a definitely determined continental tract of such ^ast 

 extent. Some geologist of the distant future viewing the embedded 

 traces of the Pleistocene glacial period of northwestern Europe and 

 northeastern North America might with almost equal assuredness 

 point out the existence of a vast continent embracing these areas and 

 the included basin of the existing North Atlantic Ocean. The geo- 

 graphical conditions peculiar to Gondwana-land are found in India, 

 Australia, and in South America from the P'alkland Islands to the 

 northern borders of the state of Sao Paulo. Representatives of this 

 flora apparently of later date occur as far north as the Mexican state 

 of Oaxaca, there with plants of a Triassic facies, Williamsonia, Zamites, 

 Otozamites, etc. (Wieland, 1909, p. 441-442). For the purpose of 

 designating the larger tracts in which this Permian flora and the 

 glacial conditions occur, Gondwana-land has thus lost its original 

 limited meaning. The south Brazilian field with its boulder-beds and 

 later Triassic trap sheets constitute a well-defined geological province 

 to-day for which the name Parana-land is quite appropriate. It is to 

 be presumed that Parana-land was conterminous with land southward 

 over Argentina and thence to the continental island group of the 

 Falklands. All three of these Gondwana areas lie within that of the 

 existing continental block. 



The question of the connection of South America with Africa in 

 Permo-Carboniferous times may be stated in other terms in a more 

 general form to be that of the origin and history of the Atlantic Ocean 

 basin, which Suess has discussed in no uncertain way. The fact that 

 there is no recognizable trace of the Atlantic Ocean along its existing 

 borders in early Triassic times, except for a narrow sea marginal to 

 the Mediterranean tract, and the fact that the Atlantic is a narrow 

 and not deep sea are quite consistent with the hypothesis of the origin 

 of this depression since Lower Triassic times. Certainly the assump- 

 tion of an Atlantic trough in Pre-Triassic times having anything like 

 the present extent of that basin must be abandoned as being with- 

 out sufficient geological evidence. Viewed in the light of Suess's 

 masterful generalization of the geology of the Atlantic shores, we find 

 no trace of the South Atlantic Ocean during the Carbonic period 

 until the possible marine episode of the Permian epoch in South 

 Africa ^ and in south Brazil if indeed these Avaters penetrated these 

 continents from the Atlantic basin. In Brazil it is more probable 

 that the sea invaded the state of Parana from the west. Without 



' Halle notes the report by Scliroeder of marine fossils above the Dwyka con- 

 glomerate in CJerman southwest Africa. Op. cit. p. 203. 



